Manual override for relief of pulsator circuit with reservoir ball valve

Abstract

A hydraulic actuator assembly of the type including a hydraulic system comprising a master cylinder, a slave cylinder, and a conduit interconnecting the master and slave cylinder. One-way valve means are provided, either mounted on the master cylinder or interposed in the conduit interconnecting the master and slave cylinders, and these valve means function to block communication between the system and the associated reservoir when the system if pressurized but allow flow of replenishing fluid from the reservoir into the system when the system is depressurized to compensate for system losses and wear in the associated vehicular mechanism. The valve further includes a manual override member in the form of a plunger which is manually depressed and which moves a valving member of the valve to a position in which it establishes communication between the reservoir port and the system port so that fluid may be moved from the system and into the reservoir even when the system is pressurized.

I claim: 
     
       1. A hydraulic actuator assembly comprising: (A) a hydraulic system including (1) a master cylinder including an input member and an output port,   (2) a slave cylinder including an output member and an input port, and   (3) conduit means providing hydraulic communication between said master cylinder output port and said slave cylinder input port whereby stroking movement of said master cylinder input member into said master cylinder delivers pressure fluid from said master cylinder through said master cylinder output port, through said conduit means and through said slave cylinder input port to said slave cylinder to extend said slave cylinder output member;     (B) valve means positioned in said conduit and including a reservoir port adapted to be connected to a hydraulic fluid reservoir, a system port communicating with said conduit, and a valving member, said valve means being operative in response to pressurization of said system to move said valving member to a closed position in which it blocks communication between said system port and said reservoir port and operative in response to depressurization of said system to move said valving member to an open position in which it establishes communication between said system port and said reservoir port to allow flow of replenishing reservoir fluid into said system or flow or fluid into said reservoir from said system; and   (C) manual override means operative when actuated to move said valving member to its open position, and thereby establish communication between said system and said reservoir port, irrespective of the state of pressurization of said system so as to allow retraction of said slave cylinder output member into said cylinder without a corresponding extending movement of said master cylinder input member out of said master cylinder.   
     
     
       2. A hydraulic actuator assembly according to claim 1 wherein: (D) said assembly further includes a reservoir communicating with said reservoir port.   
     
     
       3. A hydraulic actuator assembly comprising: (A) a hydraulic system including (1) a master cylinder including an input member and an output port,     (2) a slave cylinder including an output member and an input port, and   (3) conduit means providing hydraulic communication between said master cylinder output port and said slave cylinder input port whereby stroking movement of said master cylinder input member into said master cylinder delivers pressure fluid from said master cylinder through said master cylinder output port, through said conduit means, and through said slave cylinder input port to said slave cylinder to extend said slave cylinder output member;   (B) valve means, including a reservoir port adapted to be connected to a hydraulic fluid reservoir, a system port communicating with said conduit, and a valving member, operative in response to pressurization of said system to move said valving member to a closed position in which it blocks communication between said system port and said reservoir port and operative in response to depressurization of said system to move said valving member to an open position in which it establishes communication between said system port and said reservoir port to allow flow of replenishing reservoir fluid into said system or flow of fluid into said reservoir from said system; and   (C) manual override means operative when actuated to move said valving member to its open position, and thereby establish communication between said system and said reservoir port, irrespective of the state of pressurization of said system so as to allow retraction of said slave cylinder output member into said cylinder without a corresponding extending movement of said master cylinder input member out of said master cylinder.   
     
     
       4. A hydraulic actuator assembly according to claim 1 wherein: (D) said manual override means comprises a plunger member operative when depressed to move said valving member to its open position.   
     
     
       5. A hydraulic actuator assembly according to claim 4 wherein: (E) said valve means further includes a valve body defining said ports and defining a valve chamber containing said valving member; and   (F) said plunger member is mounted on said valve body and is movable when depressed into engagement with said valving member.   
     
     
       6. A hydraulic actuator assembly according the claim 1 wherein: (D) said valve means is rigid with said master cylinder and said system port communicates with the pressure chamber of said master cylinder.   
     
     
       7. A hydraulic actuator assembly according to claim 6 wherein: (E) said assembly further includes a reservoir communicating with said reservoir port.